This invention relates to a connector, and more
particularly to a connector of a double-lock construction.
FIGS. 9 and 10 show a conventional connector of this type. FIG. 9 shows a condition in which a retainer (terminal retainer) 1 is provisionally locked relative to a housing 2, and FIG. 10 shows a completely-locked condition.
The housing 2 has terminal receiving chambers 3, and a metal terminal 5 having an electric wire 4 clamped thereto can be inserted into the terminal receiving chamber 3 from a rear end opening 3a thereof. The retainer 1 has a cap-shape for covering a rear end portion 2a of the housing 2. As the rear end portion 2a is inserted into the retainer, the housing is provisionally locked immediately before it abuts against a rear end surface. When the rear end portion is further inserted, it abuts against the rear end surface, so that the housing is completely locked. Insertion holes 1a generally equal in shape to the rear end opening 3a are formed in the rear end face of the retainer 1, and a terminal retaining piece 1a.sub.1 extends from an upper edge of the insertion hole 1a toward the housing 2.
In the provisionally-locked condition, a lower inner surface 1b of the retainer 1 is held in contact with a lower outer surface 2b of the rear end portion of the housing 2, and each insertion hole 1a in the retainer 1 faces the corresponding rear end opening 3a of the housing 2, and the terminal retaining piece 1a.sub.1 faces the upper edge of the rear end opening 3a.
In this condition, as the metal terminal 5 having the wire 4 clamped thereto is inserted in the rear end opening 3a through the insertion hole 1a of the retainer 1, a retaining piece 5a formed on the upper surface of the metal terminal 5 is engaged with a terminal retaining pawl 3b provided within the terminal receiving chamber 3, thereby achieving a first withdrawal preventing connection. At this time, the terminal retaining piece 1a.sub.1 is disposed in facing relation to the upper edge of the rear end opening 3a and therefore will not obstruct the insertion of the metal terminal 5.
After the metal terminal 5 is inserted, the retainer 1 is pressed down in a direction indicated by arrow A (FIG. 10) so that the terminal retaining piece 1a.sub.1 can be inserted into the rear end opening 3a. The retainer is then pushed in a direction indicated by arrow B. As a result, the terminal retaining piece 1a.sub.1 moves along an upper portion of the inner surface of the rear end opening 3a and is received in the terminal receiving chamber 3, and the distal end surface of this terminal retaining piece abuts against an upper portion of a rear end of an insulation barrel 5b of the metal terminal 5 from the rear side, thereby achieving a second withdrawal preventing connection.
Since the two-step motion, that is, the pressing-down and the subsequent pushing-forward, is needed, the operativity is poor, and the arrangement is not suitable for automation.
Referring to another construction shown in FIGS. 11 and 12, FIG. 11 shows a condition in which a retainer is provisionally locked relative to a housing 2, and FIG. 12 shows a completely-locked condition.
Retaining pieces 1c, insertable respectively into terminal receiving chambers, are formed on the retainer 1 in a projected manner. A space 3c for allowing the retaining piece 1c to stand by therein is provided in an upper portion of the terminal receiving chamber 3 at a rear end portion thereof. When the retainer 1 is pushed forward after a metal terminal 5 is inserted into the terminal receiving chamber 3, the retaining piece 1c abuts against a slanting surface 2c, formed on the housing 2 and disposed forwardly of the space 3c, to be flexed downwardly, and further advances to abut against an upper portion 5c of a rear end of a contact portion of the metal terminal 5.
This connector has a problem in that since the retaining piece 1c is flexed as the retainer is pushed forward, the force required for this pushing operation increases with the increase of the number of terminal receiving chambers 3. Another problem is that after a lapse of a long time, even when the retainer is moved to the provisionally-locked position, the retaining piece 1c remains flexed downwardly, so that the metal terminal 5 cannot be withdrawn.